Prime Minister Shinzo Abe will attend the two-day Asia-Europe Meeting summit in Milan starting Thursday, the government said Tuesday.
Abe plans to meet bilaterally with other leaders and attend a meeting between Japan and the Nordic-Baltic Eight group for regional cooperation, Chief Cabinet Secretary Yoshihide Suga said.
The NB-8 comprises Denmark, Finland, Iceland, Norway, Sweden, Estonia, Latvia and Lithuania.
Ukrainian President Petro Poroshenko is likely to be one of the leaders Abe will meet, a government official said.
He is also considering making unofficial contact with Russian President Vladimir Putin in Milan before a tentative official meeting on the sidelines of the Asia-Pacific Economic Cooperation forum summit in Beijing in November.
Tokyo has faced a tough balancing act between maintaining solidarity with the West over Russia's actions in Ukraine and trying to solve bilateral issues with Moscow, most notably the long-standing dispute over the sovereignty of the four Russian-held islands off Hokkaido.
"The summit is a great opportunity for Japan to call the attention of Asian and European leaders to our efforts to contribute to global economic growth and tackle issues confronting the international community," Suga said.
Abe will also explain his attempt to make Japan a "proactive" contributor to peace, the top government spokesman added.
His Cabinet in July approved a reinterpretation of the pacifist Constitution to lift a self-imposed ban on exercising the right to collective self-defense, or coming to the defense of allies under armed attack.
Abe is scheduled to return to Japan on Saturday.